Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
110 Cards in this Set
- Front
- Back
- 3rd side (hint)
What is cellular division? |
The ability of organisms to produce more of their own kind |
|
|
What is cellular division in unicellular organisms? |
Division of one cell reproduces the entire organism. |
|
|
What is cellular division in eukaryotes? |
Development from a fertilized egg, growth, repair |
|
|
What is the definition of the cell cycle? |
The life of a cell from formation to it’s own division. |
|
|
What does most cell division result in? |
Two daughter cells with identical genetic information |
|
|
What is the exception to cell division? |
Meiosis |
|
|
What is meiosis? |
A special type of division that can produce sperm and egg cells, which produces non-identical daughter cells |
|
|
What is a genome? |
All the DNA in a cell |
|
|
What does the genome consist of? |
A single DNA molecule (common in prokaryotic cells) or a number of DNA molecules (common in eukaryotic cells) |
|
|
What makes up eukaryotic chromosomes? |
Chromatin |
|
|
What is chromatin? |
A complex of DNA and protein (histones) that condenses during cell division. |
|
|
What happens in preparation for cell division? |
DNA is replicated and the chromosomes condense |
|
|
What does each duplicated chromosome have? |
Two sister chromatids |
|
|
What are sister chromatids? |
Joined copies of the original chromosome, attached along their lengths by cohesins |
|
|
What are cohesins? |
Protein complexes that attach sister chromatids |
|
|
What is the centromere? |
The narrow waist of the duplicated chromosome where the two chromatids are most closely attached |
|
|
What do the two chromatids do during CD? |
Separate and move into two new nuclei |
|
|
What are chromatids called once separated? |
Chromosomes |
|
|
What are the two major phases of the cell cycle? |
Interphase and mitotic phase (mitosis and cytokinesis) |
|
|
What is interphase? (G1, S, and G2) |
Cell growth and copying of chromosomes in preparations for cell division. |
|
|
What is mitosis? |
The division of the genetic material in the nucleus. |
|
|
What is cytokinesis? |
The division of the cytoplasm |
|
|
What portion of the cell cycle does interphase comprise? |
About 90% of the cell cycle Cell grows during all 3 phases, but chromosomes are duplicated only during S phase |
|
|
What is G1 phase? |
First gap, cells increase in size, get ready for the S phase |
|
|
What is S phase? |
Synthesis, DNA replication occurs |
|
|
What is G2 phase? |
Second gap, cells continue to grow, gets ready for mitosis. |
|
|
What happens to the nucleus in G2 of interphase? |
A nuclear envelope encloses the nucleus. |
|
|
In G2, what do the centromeres do? |
They form regions that organize microtubules |
|
|
What is odd about chromosomes in S phase? |
They cannot be seen because they have not been condensed. |
|
|
In prophase, what happens to chromatin fibres? |
They tightly coil into discrete chromosomes, becoming visible |
|
|
In prophase, how do chromosomes appear? |
Appear as two sister chromatids joined at centromeres. |
|
|
In Prophase, what begins to form? |
The mitotic spindle begins to form and the centromeres move away from each other. |
|
|
In Prometaphase, what happens to the nuclear envelope? |
It fragments |
|
|
How do microtubules behave in prometaphase? |
Microtubules from each centrosome invade the nuclear area and the chromosomes become more condensed |
|
|
What is a kinetichore? |
Protein structure at the centromere on each sister chromatid. |
|
|
What do non kinetichore microtubules do? |
They elongate the cell |
|
|
What happens in metaphase? |
Centrosomes are at the opposites poles of the cells |
|
|
What is the metaphase plate, and what happens when chromosomes arrive there in Metaphase? |
It is an imaginary plane at the middle of the cell. Centromeres lie at the metaphase plate. |
|
|
What happens in Anaphase? |
Cohesins between chromatids are cleaved, allowing each pair to separate (becoming an independent chromosome) |
Shortest phase of mitosis |
|
Summarize mitosis in 4 points |
- two daughter nuclei form - nuclear envelope reappears - chromosomes start to decondense - mitosis is now complete, creating two genetically identical nuclei |
|
|
Summarize cytokinesis in 2 points |
Division of the cytoplasm Involves formation of a cleavage furrow, pinching cell in two. |
|
|
What is the mitotic spindle? |
A structure made of microtubules that controls chromosome movement during mitosis |
|
|
In animals, where does assembly of spindle microtubules begin? |
Begins at the centrosome. Microtubules organizing centre MTOC |
|
|
What happens to the centrosome? |
Replicates during interphase The centrosomes migrate to opposite ends of the cell during prophase and prometaphase |
|
|
What happens to the mitotic spindle during prometaphase? |
Some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes |
|
|
What are kinetochores? |
Protein complexes associated with centromeres. |
|
|
What happens to the cohesins in anaphase? |
The cohesins are cleaved by an enzyme called separase |
|
|
How do sister chromatids move in anaphase? |
The separate and move along the kinetochore microtubules toward opposite ends of the cell |
|
|
How do the microtubules shorten during anaphase? |
Depolymerization at their kinetochore ends. |
|
|
When does cytokinesis begin? What happens to the spindle? |
During anaphase or telophase, and the spindle eventually disassembles |
|
|
How does cytokinesis occur in animal cells? |
By a process known as cleavage, forming a cleavage furrow |
|
|
What forms in a plant cell during cytokinesis? |
A cell plate forms Derived from the Golgi apparatus |
|
|
What drives the cell cycle? |
Specific chemical signals present in the cytoplasm |
|
|
What directs the cell cycle? |
The cell cycle control system, which is similar to a clock |
|
|
What does the “clock” have? |
Checkpoints. The cell cycle stops until a go-ahead signal is received. |
|
|
Changes in “what” drives the cell cycle |
Changes in regulatory protein concentrations drives the cell cycle |
|
|
What are the 3 important checkpoints? |
The ones in the G1, G2, and M phases |
|
|
What happens if the cell does not receive the go-ahead? |
It will exit the cycle, switching to a non-dividing state called the G0 phase. |
|
|
What happens with cancer cells in terms of checkpoints? |
Cancer cells have lost their checkpoints due to internal and external factors |
|
|
What is meiosis? |
A special type of cell division that can produce sperm and egg cells (gametes) |
|
|
What is meiosis? |
A special type of cell division that can produce sperm and egg cells (gametes) |
|
|
What type of cells does meiosis produce? |
Non identical daughter cells |
|
|
What is heredity? |
The transmission of traits from one generation to the next |
|
|
What is heredity? |
The transmission of traits from one generation to the next |
|
|
What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
|
|
What is heredity? |
The transmission of traits from one generation to the next |
|
|
What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
|
|
What is genetics? |
The scientific study of heredity and variation |
|
|
What is heredity? |
The transmission of traits from one generation to the next |
|
|
What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
|
|
What is genetics? |
The scientific study of heredity and variation |
|
|
What are genes? |
The units of heredity and are made up of segments of DNA |
|
|
What is heredity? |
The transmission of traits from one generation to the next |
|
|
What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
|
|
What is genetics? |
The scientific study of heredity and variation |
|
|
What are genes? |
The units of heredity and are made up of segments of DNA |
|
|
What is a locus/loci? |
A gene’s specific position along a chromosome |
|
|
What do gametes do? |
Pass genes to the next generation |
|
|
How do offspring acquire genes? |
By inheriting chromosomes. Most DNA is packaged in chromosomes |
|
|
Human somatic cells have how many pairs of chromosomes? |
23 pairs. 46 total chromosomes |
|
|
What is a karyotype? |
An ordered display of the pairs of chromosomes from a cell |
|
|
What happens in asexual reproduction? |
A single individual passes all of its genes to its offspring without the fusion of gametes. |
|
|
What is a clone? |
A group of genetically identical individuals from the same parent |
|
|
What is a clone? |
A group of genetically identical individuals from the same parent |
|
|
What happens in sexual reproduction? |
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents |
|
|
What are characteristics of somatic cells? |
Non reproductive cells Two sets of chromosomes Diploid |
|
|
What are characteristics of somatic cells? |
Non reproductive cells Two sets of chromosomes Diploid |
|
|
What are the characteristics of gametes? |
Reproductive cells, sperm and eggs Half as many chromosomes as somatic cells Haploid |
|
|
How many chromosomes are in a gamete? |
A single pair Haploid number is n=23 |
|
|
For each set of 23, how many autosomes and how many sex chromosomes exist? |
22 autosomes and 1 set of sex chromosomes |
|
|
What is Aneuploidy? |
Abnormal number of chromosomes |
|
|
What are the two chromosomes in each pair called? |
Homologous chromosomes/homologs |
|
|
What are non sister chromatids? |
Chromatids in a homologous pair, one from each parents |
|
|
How many chromosomes does a diploid cell (2n) have? |
Two sets of chromosomes. For humans, the diploid number is 46 |
|
|
What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
|
|
What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
|
|
What is fertilization? what is the fertilized egg called? |
The union of gametes The fertilized egg is called a zygote. |
|
|
What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
|
|
What is fertilization? what is the fertilized egg called? |
The union of gametes The fertilized egg is called a zygote. |
|
|
What are the only type of human cells produced by meiosis instead of mitosis? |
Gametes! |
|
|
Why do fertilization and meiosis alternate in sexual life cycles? |
To maintain chromosome number |
|
|
What are the only haploid cells in animals and how are they produced? |
Gametes are haploid. Produced by meiosis and undergo no further cell division before fertilization |
|
|
What does meiosis do to the number of chromosomes? |
It reduces the number of chromosome sets from diploid 2n to haploid n |
|
|
What do the two cell divisions in meiosis produce? |
It results in four daughter cells rather than the two daughter cells in mitosis |
|
|
What two things occur in prophase 1? |
Synapsis and crossing over (Create chiasmata) |
|
|
What happens at the metaphase plate? |
Homologous pairs line up at the metaphase plate |
|
|
What is Meiosis 2? What is produced? |
Very similar to mitosis. During another round of cell division, the sister chromatids separate. This produces four haploid daughter cells |
|
|
Summarize the products of mitosis |
Conserves the number of chromosome sets Produces cells that are genetically identical to the parent cell |
|
|
Summarize the products of mitosis |
Conserves the number of chromosome sets Produces cells that are genetically identical to the parent cell |
|
|
Summarize Meiosis |
Reduces the number of chromosome sets from diploid to haploid Produces cells that differ genetically from each other and from the parent cell |
|